In integrated circuits, there are various types of devices, including logic devices, input/output (TO) devices, high-voltage devices, and the like. Different types of devices may require different power supply voltages. In an application that includes different types of devices, accordingly, a power supply circuit for converting one power supply voltage to another is needed.
In a power supply circuit, there may be a bias circuit to provide an appropriate bias voltage. A power device is biased by the bias circuit to work at a desirable state. The power device is typically large, so that it is able to provide large current needed by a load circuit.